variable_kind

tobj = WIN32OLE_TYPE.new('Microsoft Excel 9.0 Object Library', 'XlSheetType')
variables = tobj.variables
variables.each do |variable|
  puts "#{variable.name} #{variable.variable_kind}"
end

The result of above script is following:
  xlChart CONSTANT
  xlDialogSheet CONSTANT
  xlExcel4IntlMacroSheet CONSTANT
  xlExcel4MacroSheet CONSTANT
  xlWorksheet CONSTANT